Apparatus for maintaining the alignment of a moving web



April 5, 1966 1.1.. Flr-'E ETAL APPARATUS FOR MAINTAINING THE ALIGNMENTOF A MOVING WEB Filed Sept. 50, 1963 2 Sheets-Sheet 1 April 5, 1966 1. 1FlFE ET AL 3,244,340

APPARATUS FOR MAINTAINING THE ALIGNMENT 0F A MOVING WEB Filed Sept. 50,1963 2 Sheets-Sheet 2 AAI-m 2 55'.- 5 2 -Z Ez-5 Arme/vers United States`Patent Oliice 3,244,340 Patented Apr. 5, 1966 APPARATUS FOR MAINTAININGTHE ALIGN- MENT OF A MOVING WEB Irwin L. Fife and BruceA. Feiertag,Oklahoma City, Ghia., assignors to Fire Manufacturing Company, Inc.,ldahoma City, Okla., a corporation of Oklahoma Filed Sept. 30, 1963,Ser. No. 312,741 16 Claims. (Cl. 226-22) This invention relatesgenerally to apparatus for shifting moving web of tlexible sheetmaterial for the purpose of maintaining the web in alignment with apredetermined path of travel. More particularly, but not by way oflimitation, the present invention relates to apparatus used toautomatically maintain a moving or traveling web in alignment with apredetermined path of travel by initiating a corrective shift of the webin response to an automatically detected misalignment thereof.

This application concerns web-guiding assemblies of the general typedisclosed in application for United States Letters Patent Serial No.72,050 tiled November 28, 1960, now U.S. Patent 3,104,789, and assignedto the assignee of the present invention. Inthe cited U.S. Patent3,104,789, a device has been described for maintaining the alignment ofa moving web which generally comprises a cantilevered guide roller whichbears against the web to be maintained in alignment, and which isautomatically shifted in response to signals generated by departures ofthe web from the desired path of travel. The advantages of thecantilevered roller type web guiding device have been discussed inconsiderable detail in said U.S. Patent 3,104,789 and it will suffice tosay at this point that such cantilevered roller web guiding devices maybe used effectively in many situations where web guiding rollerssupported at each of their ends either cannot be used at all, or areextremely difficult or inconvenient to use. In the embodiments of thecantilevered roller type web guiding device described in the cited U.S.Patent 3,104,789, departures of the web to be guided from the desiredpath of travel are sensed by means of a pneumatic sensing head whichtransmits signals in the form of variations in pneumatic pressure to apressure responsive diaphragm. The diphragm in turn actuates an armsupporting the web guiding roller in the nature of a cantilever so as toshift the arm about a pivotal axis extending parallel to the bisector ofthe angle subtended by the spans of the web approaching and leavingthe'web guiding roller. The arm which is actuated in such device inresponse to s ignals from the pneumatic sensing head is an elongatedmember which is angled to permit the rollers to be supported therefromas a cantilever, and to extend in a direction which permits the web tobe wrapped about the roller in a certain necessary predeterminedconguration. Thus, as explained in U.S. Patent 3,104,789, it is alwaysnecessary t-hat the angle which is subtended by that portion of theperiphery of the cylindrical roller contac-ted by the web have abisector which extends substantially parallel to the pivotal axis of thearm which supports the roller. The actuation of the roller by themovement of the supporting arm is, in effect, one of movement in adirection which is transverse with respect to the path of travel of theweb, and which is simultaneously an angling or canting movement in whichVthe roller is pivoted about the pivotal axis of the supporting arm.

Although the embodiments of the invention described in U.S. Patent3,104,789 are characterized by marked advantages in many types of useover the web guiding roller devices in which the roller is supported atboth of its ends, the configuration and size of the roller supportlingarm and the manner in which the arm and roller are mounted sometimesresult in inconvenience or difficulty in finding or developing a properposition for mounting the web guiding device in view of the path oftravel which must be followed by the web as determined by the necessarylocation of the source and destination of the web. Moreover, theemployment of a pneumatic power source for shifting the roller inresponse to departures of the web from the desired path of travel, whileproviding satisfactory operation in the case of relatively small webguiding assemblies involving less massive rollers, is not entirelysatisfactory in heavier assemblies in which very large web guidingrollers must be substantially instantaneously shifted in response toslight departures of the web from precise alignment. This is due to thefact that the compressible gas used as the power fluid does not asinstantaneously transmit the actuating signals in the form of pressurevariations as would a non-compressible or hydraulic fluid, and is moresubject to power losses due to friction in the system. Thesedisadvantages of the compressible fluid are particularly pronouncedwhere the power to be transmitted is relatively great and the `distancebetween the sensing head and the arm or roller actuating structure isrelatively great.

The present inventionV provides a roller type web guiding assembly inwhich the roller supporting structure and actuating mechanism isrelatively compact and can be easily located in any desired position inorder to accomplish a particular web guiding task. In a preferredembodiment of the invention, the roller used for guiding the web issupported in the nature lof a cantilever. The web guiding roller is moreeasily wrapped with the web than in the case of devices constructed -inaccordance with the disclosure of the cited U.S. Patent 3,104,789, andthe roller is actuated in its corrective movements by a noncompressiblehydraulic power fluid which permits considerably more massive rollers tobe shifted in instantaneous response to automatically correct departuresof the guided web from a predetermined path of tr-avel. The manner inwhich a roller is mounted upon its supporting assembly better adapts theroller to be actuated by the hydraulic drive system used in theinvention. Moreover, the employment of the hydraulic power `iiuid forshifting the roller is accomplished without loss of the high sensitivitydeveloped by pneumatic type sensing heads as used in the web guidingassembly described in said U.S. Patents 3.104.789.k

VIn one of its broader aspects, the present invention is a web guidingsystem comprising a roller or generally cylindrical web guiding memberwhich extends substantially transversely to the path of travel of theweb to be guided with an arcuate portion of the periphery of the rollerin frictional contact with the web; a slidably mounted bearing blockwhich is mounted for linear, reciprocating movement in a path extendingsubstantially transversely to the path of movement of the web, whichbearing block pivotally supports an arm which rotatably journals theroller so that the axis of pivotation of such arm and the roller itcarries extends through, and is substantially normal to, the axis ofrotation of the roller; a camming or guiding device contacting theroller supporting means and pivoting the roller supporting means in thebearing block which supports it during the sliding movement of thebearing block during operation of the device; and means for shifting thebearing block transversely with respect to the longitudinal axis of themoving web in response to transverse movements of the web relative toits desired path of travel so that misalignment of `the web from saidpredetermined path of travel is efectively automatically corrected. Fromthis brief and summary description of the invention, it will immediatelybe perceived that the preferred embodiment of the present invention inAwhich a cantilevered roller is used in the web guiding assembly of theinvention differs from the assembly described and depicted in saidcopending application in that the pivotal axis of the roller and itssupporting means extends through and substantially normal to the axis ofrotation of the roller as opposed to being displaced laterally from suchaxis. This arrangement permits the device of the present invention to bemade in considerably more compact form, and ultimately results in thestructure being better adapted for mounting in various positionsnecessitated by the particular path followed by the web which is to beguided.

To more specifically describe one embodiment of the present invention,the means which is provided for shifting the slidably mounted bearingblock in response to transverse movements of the web relative to itsdesired path of travel includes a pneumatic sensing head which respondstotransverse movements of the longitudinal edge of the moving web bydeveloping variations in the pneumatic pressure developed across thesensing head. The pressure variations are transmitted to a servo valvesystem in which the pneumatic pressure is converted to hydraulicpressure which is in turn used to drive or shift the slidably mountedbearing block. The hydraulic power for driving the moving elements ofthe assembly is delivered to the slidably mounted bearing block throughthe instrumentality of a double acting hydraulic cylinder which, becauseof the particular mounting arrangement of the web guiding roller, can bemounted in either of two alternate positions with respect to the rollersupporting structure and thereby permit the assembly to be more easilypositioned properly with respect to the web which is to be guided. As anexample of the power arnpliication which is obtainable when thepneumatic-hydraulic sensing drive system is employed for shifting theroller in response to undesirable movements of the web to be guided, wehave found that a pneumatic force of 2 lbs. can control forces of asmuch as 1800 lbs. at the hydraulic cylinder through the instrumentalityof the pneumo-hydraulic servo valve hereinafter described.

An additional feature of the present invention is the provision of anautomatically actuated servo centering valve which may be used in lieuof the pneumatic sensing head to automatically precisely center the webguiding roller with respect to the desired path of travel of the web.This feature of the invention enables the web guiding roller to becentrally positioned relative to the desired path of travel prior tothreading the web over the roller, and thus avoids the problem of havingthe roller constantly shifting during such threading procedure as aresult of inadvertent shifting of the web relative to the sensing head.The procedure of threading the web into the web guiding apparatus isthus considerably expedited.

From the foregoing description of the invention, it will have becomeapparent that it is a major object of the present invention to providean improved cantiievered roller type web guiding apparatus formaintaining the alignment of a traveling web according to a desiredpredetermined path of travel.

A further object of the present invention is to provide a cantileveredroller type web guiding assembly which is compact and which may be moreeasily mounted for the purpose of guiding webs which it is desired tomove in fixed or inalterable paths of travel.

An additional object of the present invention is to provide an automaticweb aligning device which is hydraulically actuated and thereforecapable of effectively guiding webs of substantially larger transversewidth and greater density and weight.

A further object of the present invention is to provide in a web guidingdevice, a web guiding roller which may be precisely centered withrespect to the desired path of travel of the web prior to threading theweb over the roller so that such threading procedure may be more easilyand expeditiously accomplished.

' Other objects and advantages in addition to those hereinbeforedescribed will appear in the following detailed description of theinvention, or will be apparent from a reading thereof in conjunctionwith a perusal of the accompanying drawings which illustrate myinvention.

In the drawings:

FIGURE l is a schematic illustration of one embodiment of the Webguiding or aligning system of the present invention with the web guidingroller and its supporting structure illustrated in perspective.

FIGURE 2 is a side elevational View of the cantilevered web guidingroller of the present invention, and one type of supporting structurewhich may be used therewith.

FIGURE 3 is a view in section taken along line 3-3 of FIGURE 2.

FIGURE 4 is a view in section taken along line 4-4 of FIGURE 2.

FIGURE 5 is an end View of a single roller type of web guiding structureas the same is viewed from its end at which the servo centering valveused in one ernbodiment of the invention is located.

FIGURE 6 is a view similar to FIGURE 5 but illustrating a dirTerentembodiment of the invention in which two web guiding rollers areprovided.

Referring now to the drawings in detail, and particularly to FIGURE 1, aweb which it is desired to retain in a predetermined path of travel isdesignated by reference character 1t). The webs which it is the purposeof the present invention to maintain in alignment are iiexible elongatedsheet materials and may be constructed of paper, brous material, sheetmetals and other materials well known in the art. Alignment of the webis maintained by contact with a cylindrical guide means or rollerdesignated generally by reference character 12, which roller is moved inthe operation of the device in a proper direction and by a proper amountto shift the web 10 from a misaligned to an aligned condition. It willbe understood, of c-ourse, the the web 1t) moves from a feed roll orsource roll toward a takeup or terminal roll in accordance withpractices well understood in the art. The web 10 is wrapped around aportion of the arcuate periphery of the roller 12 so as to definebetween its incoming span 10a and its outgoing span 10b, an angle, theposition of which relative to the circumference to the roller is ofconsiderable importance and will be dealt with in greater detailhereinafter.

In the embodiment of the present invention illustrated in the drawings,the roller 12 is journaled at one of its ends in a supporting arm 14which comprises a journaling plate or bracket 16 which rotatablyreceives the shaft 17 of the roller, and a base plate 18 which extendsparallel to the longitudinal axis of the roller. As an alternativeconstruction, instead of journaling the axis of the roller 12 forrotation relative to the bracket 16, the roller shaft 17 may be fixed tothe bracket 16 and the roller 12 rotatably mounted on the shaft 17 bythe use of suitable bearings (not seen). In a preferred embodiment ofthe present invention, the base plate 18 is provided with suitabletapped recesses 20 at each of its ends so that the bracket 16 may besecured to either end of the base plate 18 by suitable threaded screwsor bolts. This flexibility in the mode of mounting of the bracket 16facilitates the use of the web guiding assembly in a variety ofdifferent positions as may be dictated by the fixed course whichy mustbe followed by the web in its travel. In other words, in some instances,the ability to mount the bracket 16 on either end of the base plate 18may result in a much simplerand less expensive installation than werethe bracket 16 to be positionable upon only one end of the base plate.

As shown in FIGURE 2, the base plate 18 is rotatably supported by abearing block 22 which journals a shaft 24 secured to the under side ofthe base plate 18. The bearing block 22 is in turn slidably mounted on araceway assembly designated generally by reference character 26 whichincludes a pair of guide rods 28 upon which the bearing block isreciprocated. The guide rods 28 extend substantially parallel to eachother, are of substantially equal length and are supported by a fixedsupporting structure designated generally by reference character 30. Thefixed supporting structure 30 is generally U-shaped in configuration andhas :a pair of opstanding legs 32 which receive and support the guiderods 28.

A plate 34 is secured to one of the upstanding legs 32 and carries aroller 36 which tracks in one of a pair of arcuate slots 38 formed inthe opposite ends of the base plate 18. The arcuate slots are curved sothat as the bearing block 22 is reciprocated on the guide rods 28, theroller 36, which is fixed, imparts a swiveling or canting motion to thebase plate and to the web guiding roller 12. The roller 36 thus acts asa cam follower and the slot 38 as a cam in imparting the swiveling orangular movement to the base plate 18 and to the cantilevered roller 12supported thereby. In providing the arcuate slots 38 at each end of thebase plate 18, the web guiding system is rendered more versatile in thatthe web guiding roller 12 and its supporting base plate 18 may, when theplate 34 and roller 36 are removed from the assembly, be rotated through180 to relocate the open or unsupported end of the web guiding roller12. The plate 34 and roller 36 may then be replaced so that ,the roller36 tracks in the slot 38 at the opposite end of the roller.

Reciprocation of the bearing block 22 on the guide rods 28 is effected,in one embodiment of the invention, by a double acting hydrauliccylinder assembly designated generally by reference character 40. Thedouble acting hydraulic cylinder assembly 48 is secured to one end ofthe fixed supporting structure 30 through the plate 34. The doubleacting hydraulic cylinder assembly 4t) includes a cylinder 44 having apair of hydraulic uid intake and discharge conduits, 46 and 48,connected thereto, and a hydraulically actuated piston rod 50 (see FIG-URE 2) which extends slidably through the plate 34 and the upstandingleg 32 and is secured to the bearing block 22. It will be perceived thatactuation of the piston rod 50 by the introduction of a hydraulic powerfiuid to the hydraulic cylinder 44 will cause the slidably mountedbearing block 22 to be reciprocated upon the guide rods 28 with thedirection of reciprocation depending upon whether the power fluid entersthe cylinder 44 through the conduit 46 or through the conduit 48. At itsside opposite the side to which the piston rod 50 is attached, thebearing block 22 carries an actuating rod 51 which extends parallel tothe guide rods 28 and is tapered at its free end as shown in FIGURES 2and 4 to permit it to slide upon and depress the valve stern of a servocentering valve 104 hereinafter described.

The portion of the web aligning system of the invention which, in oneembodiment of the invention, is utilized to sense the departure of theweb from a desired predetermined path of travel and to convert suchsensations to a signal employed to change the position of the guideroller 12 is illustrated in FIGURE l. A supply of compressed air isrepresented by reference character 52 and preferably comprises apositive displacement, vane type compressor capable of supplying apulsating air pressure of relatively high frequency pulsations, such asthe compressor shown and described in application for United StatesLetters Patent Serial No. 175,590, filed February 26, 1962, now U.S.Patent 3,098,595, and assigned to the assignee of the present invention.Pulsating air pressure from the air compressor 52 is delivered via aconduit 54 to the intake port of a pneumatic sensing head 56, and by theair pressure manifold 58 to the dither uid chamber 68 of a main servovalve designated generally by reference character 62.

A servo valve of the general type illustrated in FIG- URE 1 in oneembodiment of the present invention is illustrated and described indetail in U.S. Patent 3,098,595

hereinbefore cited. The servo 4valve 62` comprises gen-` erally afour-way hydraulic valve, indicated generally by the reference character64, and a pneumatic servo valve actuator designated generally byreference character 66. The pneumatic servo valve actuator 66 includesthe dither fiuid chamber `60 and a control fluid chamber A68. Thecontrol fluid chamber 68 and dither fiuid chamber 60 of the pneumaticservo valve actuator are separated or partitioned from each other by aflexible diaphragm 70. A second diaphragm 72 provides a seal around theshaft 74 of the spool 76 of the four-way hydraulic valve 64 so that theair in the dither fluid chamber 60 cannot commingle with the hydraulicfluid being passed through the four-way hydraulic valve. An adjustingscrew is threaded through the pneumatic servo valve actuator housing atone end thereof and is axially aligned with the valve spool 76. Alocknut 82 may be provided to secure the adjusting screw 8i) at anydesired position. A coiled spring 84 is disposed between the diaphragm70 and a spring plate 86 on the end of the adjusting screw.

Communication between the air pressure manifold 58 and the control fluidchamber 68 is established through a conduit 90 which contains arestricting orifice 91. The control fluid chamber 68 is also entered bya conduit 92 which passes through a suitable electrically energizedsolenoid valve 94 to the pneumatic sensing head 56.

. Reference character 96 designates an adjustable, constant pressureregulator which is connected to the manifold S8 by conduit 98 and whichfunctions to maintain the pressure within the manifold 58 at a selectedaverage value. The pressure regulator 96 has a low frequency response soas not to attenuate the high frequency pressure pulsations developed bythe positive displacement compressor 52.

Yet another conduit which communicates with the control fiuid chamber 68is the conduit 100 which passes through an electrically energizedsolenoid valve 162 and is connected to a servo centering valve 104 whichis positioned at one end of the raceway assembly 26 as seen `in FIGURE 1and best illustrated in FIGURES 2 and 4. The servo centering valve has avalve stem 106 which projects therefrom and cooperates with theactuating rod 51 in the manner previously mentioned. The purpose of theservo centering valve 104 will be explained in detail hereinafter.

The four-way hydraulic valve 64 may be of any suitable design, and isshown as having a valve spool 76 reciprocally mounted in a valve cavity110 in a housing 112. A power fluid inlet port 114 communicates with thecavity 110 through the housing 112 and is connected to a conduit 116 bywhich the valve is supplied power fiuid from a conventional hydraulicpump 118 which draws hydraulic fluid from a reservoir 120 through ahydraulic line 122. A return line 123 to the reservoir 128 is providedfrom the pump 118 so that when a substantial back pressure on the pumpdevelops as a result of the complete closure of the four-way hydraulicvalve 64, the pump can recycle iuid to the reservoir 120. A pair ofexhaust fluid ports 124 and 126 are formed through the housing 112 andcommunicate with the cavity 110. The exhaust fluid ports 124 and 126 areconnected via a conduit 130 to the hydraulic fluid reservoir 128. A pairof power fiuid outlet ports 132 and 134 are connected via the conduits46 and 48, respectively, to the double acting hydraulic cylinderassembly 40. The details of the construction of the four-way hydraulicvalve 64 are described in copending application for United StatesLetters Patent Serial No. 175,590, to which reference has hereinbeforebeen made.

Operation The first procedure in operating the web guiding systern ofthe present invention is to thread the web over the web guiding roller12. This may usually be more easily accomplished where the roller iscantilevered as shown in the accompanying drawings. The web 10 may bethreaded over the roller 12 when the web guiding system of the inventionis in either of two statuses. In one of these, the,

system is set for automatic guiding by switching an electrical switch140 to a position in which the solenoid valve 102 is closed so that nopneumatic pressure is delivered via the conduit 100 to the .servocentering valve 1h14. In this position of the switch 140, the solenoidvalve 94 is opened to permit the pneumatic pressure developed across thesensing head 56 to be transmitted as a static pressure through theconduit 2 into the control fluid chamber 68. The magnitude of thepressure developed in the conduit 92 and in the control fluid chamber 68will then depend upon the position of the web 10 relative to the sensinghead 56. In other words, the more of the air jet across the slot in thesensing head 56 which is intercepted or cut olf by the web itl, thelesser will be the pressure developed in the control fluid chamber 68.The manner in which the sensing head 56 functions to vary the pressurein the control fluid chamber 68 is fully described in copendingapplication for United States Letters Patent Serial No. 175,590. Thepressure developed in the control fluid chamber- 68 acts in oppositionto the pressure developed in the dither fluid chamber 66 so that apressure differential existing across the diaphragm 70 causes the spool'76 of the four-way hydraulic valve 64 to be shifted in the housing 112.The manner in which the fluctuations in the pressure developed in thecontrol fluid chamber 68 are employed to correct misalignment of thetraveling web 16 will be explained in greater detail hereinafter.

The second, and the preferred, status of the web guiding system at thetime of threading the web lt? over the cantilevered web guiding roller12 is that in which the control switch 140 is shifted to a secondposition which effectively closes the solenoid valve 94 and opens thesolenoid valve 102.. This permits air pressure to be transmitted throughthe conduit 10d to the servo centering valve lll-4. At the same time,the sensing head 56 is effectively removed from the system since no aircan flow from the sensing head through the conduit 92 into the controlfluid chamber 68. The pressure in the control lluid chamber 68 thus doesnot vary in response to variations in pressure resulting from thechanging position of the web I@ relative to the sensing head 56. On theother hand, the fluid pressure in the control iluid chamber 68 isdetermined solely by the average pressure established in the manifold Sby the pressure regulator 96 and the amount of pressure which is bledfrom the control fluid chamber 68 through the servo centering valve 104.

The amount of fluid which is bled through the servo centering valve l04is in turn determined by the degree to which the valve stem IGS isdepressed by the actuating rod 51. The system is designed so that byproper preadiustment of the adjusting screw Sti and proper control ofthe pressure in the manifold 53 by the pressure regulator 96, the fluidbled through the servo centering valve 04 may be made to be justsuilicient to exactly position the spool 76 of the four-way hydraulicvalve 64 in a position in which the web guiding roller l2 will beexactly centered relative to the desired path of travel of the web lll.In other words, the servo centering valve 104 is a device whichfunctions to permit the roller l2 to be precisely centered with respectto the desired path of travel of the web so that the web may be threadedthereon at that time Without the roller being constantly shifted inresponse to the changing position of the portion of the web which passesthrough the sensing head 56. The sensing head 56 is effectively isolatedfrom the system and the only pressure variation which effects theposition of the web guiding roller l2 is that which occurs as a resultof the bleeding of air from the control fluid chamber 63 through theservo centering valve 104.

In threading the web l@ upon the cantilevered web guiding roller 12, theincoming and outgoing spans, Illa and b respectively, of the web it?should denne an angle, the bisector of which is coincident with, or liesin the plane occupied by, the pivotal axis of the roller l2. Thispivotal axis is, of course, the pivotal axis of the shaft 2li which issecured to the bottom of the base plate 18 and which is rotatablyjournaled in the slidably mounted bearing block 22. As explained indetail in the hereinbefore identified U.S. Patent 3,104,789, thisarrangement of the web relative to the pivotal axis of the web guidingroller 1?; is important to the most efficient functioning of the rollerl2 in correcting misalignment of the web lll.

After the web l@ has been passed partly around the roller 12, thecontrol switch 14) is shifted to the automatic operating position inwhich the solenoid valve 102 is closed and the solenoid valve gli isopened. This effectively isolates the servo centering valve 104 from thesystem and establishes communication between the sensing head 55 and thecontrol fluid chamber 63. As the lateral edge of the web lll movestransversely in the slot in the sensing head 104.-, it passes throughthe air jet developed across the sensing head by the pressurized airdelivered from the conduit 5d and received by the conduit 92. Themagnitude of the pressure developed in the conduit 92, and therefore ofthe pressure developed in the control fluid chamber 68 defends upon thedegree to which the web llt) intercepts the air jet passing across theslot in the sensing head 56.

The position of the diaphragm 7@ in the pneumatic servo valve actuator66 is determined by the pressure of the air in the control fluid chamber68 and the pressure of the air in the dither fluid chamber 6d. Thepressure pulsations developed by the compressor 52 are transmitted tothe dither fluid in the ditlier fluid chamber 60 and function to vibratethe diaphragm '70 at a high frequency so that the spool 76 of thefour-way hydraulic valve will not become stuck or frozen in any oneposition in the cavity llt?. The average pressure of the dither fluid,however, is governed by the setting of the adjustable pressure regulator96 and is adjusted to a magnitude such that the pressure induced in thelluid control chamber 68 when the lateral edge of the web lt) is in theproper position of alignment relative to the sensing head 56 willexactly balance the average pressure in the dither fluid chamber 60combined with the mechanical pressure on the diaphragm developed by thespring 84. With the pressure on opposite sides of the flexible diaphragm'70 thus balanced, the spool 76 of the four-way hydraulic valve 64 ispositioned so that no hydraulic fluid passes through either of theconduits 4t? and ed into the hydraulic cylinder 44. This position of thevalve spool 76 is illustrated in FlGURE l. The equalization f hydraulicpressure on opposite sides of the piston in the hydraulic cylinder 44results in the piston being centered in its cylinder, and in the bearingblocl; Z2 being centered on the guide rods 26. The cantilevered guideroller l2 is thus centrally positioned with respect to the longitudinalaxis of the web and is not canted or swiveled at any angle with respectto the transverse axis of the web. rThe described alignment of thecantilevered roller 12 will persist as long as the Web lll moves in thepredetermined desired path of travel and does not shift laterally fromsuch path in either direction.

When the web l@ commences to shift from the desired predetermined pathof travel under external influences, such as vibration, air currents orother forces well known to those skilled in the art, the lateral edge ofthe web is also shifted relative to the pneumatic sensing head 56 whichis xed in its position. As the lateral edge of the web l@ moves fartherinto or out of the air jet directed across the slot in the sensing head56, the pressure prevailing in the conduit 92 is altered, thus causingan increase or decrease in the pressure in the control fluid chamber 68.

lf, for example, the we-b moves to the right as viewed in FIGURE. l andthus moves farther into the slot in the sensing head 56, a greaterobstruction of the air jet across `the sensing head occurs with theresult that the pressure in the conduit 92 is decreased. The decrease inpressure in the conduit' 92 causes a corresponding decrease in thepressure existing in the control fluid chamber 68 o-f the pneumaticservo valve actuator 66. The higher pressure exerted by the dither uidon the opposite side of the diaphragm 7 0 will then cause the diaphragmto flex into the control fluid chamber 68 resulting in a shift of thespool 76 of the four-way hydraulic valve toward the left. A shift by thespool 76 of this type will result in the discharge port 132 of thefour-way hydraulic valve lbeing closed and the discharge port 134 beingopened to receive hydraulic fluid from the pump 118. Hydraulic fluid isthus directed through the conduit 48 to the outer end of the hydrauliccylinder` 44 so that lthe piston rod 50 is caused to move to the left.Movement of the piston rod 50 to the left is ac-companied by thedischarge of hydraulic liuid through the return conduit 46 to thefourway hydraulic valve 64 and results in the slidably mounted bearingblock 22 being moved toward the left as viewed in FIGURE l. Thismovement of the bearing block 22 in turn causes the lbase plate 1S to beshifted to the left. As the base plate 18 is moved toward the left, thebase plate and the cantilevered guide roller 12 which it supports areswiveled in a pivoting movement as a result of the tracking of theroller 36 in the arcuate slot 38. The curvature of the slot 38. is suchthat the base plate 18 and cantilevered roller 12 supported thereby willlbe swiveled in a direction which moves the free end of the roller inthe general direction of travel of the web and the supported end of theroller in the general direction of the origin of the web. This movement,coupled with the transverse movement of the roller 12 as the bearingblock 22 slides along the guide rods 28, will cause the web 1li to moveoutwardly in the slot in the sensing head 56.

As the web 10 moves outwardly in the slot in the sensing head 56, itpresents less interference with the air jet across the sensing head slotso that the pressure in the conduit 92 is increased. The increase in thepressure in the conduit 92 is reflected by an increase in the pressurein the control fluid chamber 68 which in turn fiexes the diaphragm 70toward the dither fluid chamber 6G. This moves the spool 76 and thefour-way hydraulic valve toward the right as shown in FIGURE l with theresult that the discharge of hydraulic iluid through both or" the ports132 and 134 is stopped and the piston in the hydraulic cylinder 44 isarrested when it has arrived at approximately the center yof thecylinder. The web guiding roller 12 will therefore cease its movementand the web will remain in its realigned position until such time asother external iniiuences tend to move it out o-f alignment with itspredetermined path of travel and thus further into or out of the slot inthe sensing head 56.

If the web becomes misaligned by movement in la direction which movesits lateral edge outwardly in the slot in the sensing head 56, thecorrective action which occurs is the opposite of that which has beendescribed for inisalignmeiit tending to move the Web inwardly in theslot in the sensing head. In other words, the pressure in the controlfluid chamber 68 is increased so that the spool J76 of the four-Wayhydraulic valve 64 is moved to the right. from the pump 11S through thefour-way hydraulic valve 64 and into the conduit 46 which in turndelivers the lluid to the inner end of the hydraulic cylinder 44. Thepiston rod 1S is thus moved to the right, d-rawing with it the bearingblock 22 which in turn causes the cantilevered web guiding roller 12 tobe moved t-o the right or toward the sensing head 56. At the same time,the roller is swiveled in a direction which causes it to exert lesserpressure on the lateral edge of the web toward which it ismoving than onthe opposite edge of the web. In this manner, the movement of the webtoward the left or outwardly in the slot in the sensing head is offsetby the opposite lmovement of the roller and the web is returned to itsaligned position.

From the foregoing description of the invention, it will be perceivedthat the embodimentv of the cantilevered This permits hydraulic fluid tobe delivered roller web guiding assembly hereinbefore described is aconsiderably more compact system than that which has 4been described inthe copending application of which this application is acontinuation-in-part. Moreover, a pneuino-hydraulic sensing power drivesystem has been illustrated which permits much heavier guide rolls to bemoved in substantially instantaneous and rapid response to variations inthe path of web travel from that which has been predetermined to bedesirable. It is to -be borne in mind that the novel roller supportingmechanism and pneumo-hydraulic drive system of the invention may also beemployed to advantage in systems in which the roller is supported atboth of its ends.

Although a number of modilications and variations may be made in thedetails of structure which have hereinbefore been described by Way ofexample, it is intended that insofar as such variations andmodifications do not depart from a reliance upon the basic principleswhich underlie the present invention, such changes are intended to becircumscribed by the spirit and scope of the present invention except asthe same may be necessarily limited by the appended claims or reasonableequivalents thereof.

What is claimed is:

1. .web guiding system for guiding a traveling web comprising:

(a) a cantilevered roller extending transversely to the path of travelof said web with an arcuate portion of bits periphery in frictionalengagement with said we (b) a raceway assembly;

(c) means slidably and reciprocably mounted on said raceway assembly forpivotally supporting said cantilevered roller;

(d) means on said racew'ay assembly and cooperating with said rollersupporting means-for pivoting said cantilevered roller relative to saidraceway assembly and the longitudinal axis of said web as said rollersupporting means reciprocates on said raceway assembly; and

(e) means for correlating the transverse movements of said web relativeto a predetermined path of travel with movements of said cantileveredroller and roller supporting means to maintain the transverse alignmentof said web.

2. A web guiding system as claimed in claim 1 wherein said slidably andreciprocably mounted roller supporting means comprises:

(a) a bearing block slidably mounted on said raceway assembly; and

(b) an arm pivotally journaled in said bearing block for pivotationabout an axis extending substantially normal to the plane in which saidbearing block slides, said arm being secured to one end of said rollerand supporting said roller in the nature of a cantilever in a planeextending substantially parallel to the plane in which said bearingblock slides.

3. A web guiding system as claimed in claim 1 wherein said means forcorrelating the transverse movements of said web relative to apredetermined path or" travel with the movements of said cantileveredroller comprises:

(a) means sensing the transverse movement of said web relative to apredetermined path of travel; and

(b) means actuated by said sensing means for reciprocating saidcantilevered roller supporting means in the opposite direction from thedirection of sensed transverse movement of said web.

4. A web guiding system as claimed in claim 3 wherein said ysensingmeans comprises:

(a) a slotted sensing head for receiving one edge of the web;

(b) means for developing a iluid flow across the slot in said sensinghead; and

(c) means responsive to variations in the pressure of said fluid toactuate said means for reciprocating said cantilevered roller supportingmeans.

5. A web guiding system as claimed in claim 3 wherein said means forreciprocating said cantilevered roller supporting means is a hydraulicpower system including (a) a double acting hydraulic cylinder having apiston therein connected to said cantilevered roller supporting means;

(b) a source of hydraulic power fluid;

(c) conduit means connecting said source of power uid to said cylinder;

(d) a pump in said conduit means; and

(e) valve means responsive to said sensing means in said conduit meansfor directing varying amounts of power iuid to opposite ends of saidhydraulic cylinder.

6. A web guiding system as claimed in claim 1 and further charcterizedto include means for automatically positioning said roller normal to thedesired path of travel of said web to facilitate threading said webthereon at the commencement of the guiding of the web.

'7. A web guiding system as claimed in claim 6 Wherein said means forautomaticaly positioning said roller normal 'to the desired path oftravel of said webI comprises:

(a) means for disengaging said correlating means from the system; and

(b) ymeans for automatically moving said roller supporting means to thecenter of said raceway assembly whereby .when said raceway assembly isproperly located relative to the desired path of travel of said lweb,said roller and said Iroller supporting means are positioned normal tosaid desired path of travel.

S. Apparatus for maintaining the transverse alignment of a moving webcomprising:

(a) means sensing the transverse movement of said web relative to apredetermined path of travel;

(b) a roller extending transversely to the path of travel of said webwith an arcuate portion of its periphery in frictional engagement withsaid web;

(c) a rigid member rotatably supporting said roller in the nature of acantilever;

(d) a fixed supporting member;

(e) a connecting linkage slidably mounted on said supporting member andpivotally connected to said rigid member; and

() guide means on said rigid member cooperating with said connectinglinkage to pivot said roller about an axis extending substantiallyparallel to the bisector of the angle subtended by said arcuate portionof the periphery of said roller.

9. In combination with a moving web', apparatus tor maintaining said'web in transverse alignment with a desired path ot' travel, saidrapparatus comprising:

(a) fa generally cylindrical memlber extending across the path of travelof said web and bearing against said web to form a lbight therein;

(b) an arm rotatably journaling one end of said generally cylindricalmember in the nature of `a cantiliver;

(c) a `block pivotally supporting said arm for pivotation of said rollerabout an axis extending substantially parallel to the bisector of thearc formed by said bight;

(d) a fixed raceway slidably journaling said Iblock for movement in adirection generally normal to the direction of travel of said web;

(e) means secured to said raceway and acting on said arm during movementof said block to pivot said arm `and roller about said pivotal axis;

(f) means sensing the transverse movement of said web relative -to adesired path of travel; and

(g) means actuated by said sensing means for sliding said block alongsaid raceway to elect correction of the misalignment of said web.

10. The combination Vclaimed in claim 9 wherein said sensing meanscomprises:

(a) Ia compressible liuid operated sensing head for producing a controlsignal which varies in accordance with the position of the lateral edgeof said web relative to said sensing head, said sensing head having ailuid input port and a lluid output port for transmitting the controlsignal fluid pressure;

(b) means for supplying a pressure uid to said input port;

(c) diaphragm means responsive to variations in the pressure of thefluid in said outlet port; and wherein said means actuated by saidsensing means for sliding said block along said raceway comprises:

(l) a source of a liquid power fluid; (2) a pump connected to saidsource; (3) a double acting hydraulic cylinder;

(d) a piston rod connected to said block at one of its ends and having apiston on its other end disposed in said cylinder;

(e) means for conveying power fluid from said pump to each of the endsof saidy hydraulic cylinder; and

(f) valve means in said power fluid conveying means and connected tosaid diaphragm means for actuation thereby whereby the amount of powerfluid conveyed to the respective ends of said cylinder is dependent uponthe degree and direction of response of said diaphragm to variations inthe pressure of said compressible lluid in the outlet port of saidsensing head.

11. The combination claimed in claim 16 and further characterized toinclude means for dithering said diaphragm at a high frequency and lowamplitude whereby sticking of said valve means is prevented.

12. In combination with a moving web, apparatus for maintaining said webin transverse alignment with a desired path of travel, said apparatuscomprising:

(a) -a generally cylindrical member extending across the path of travelof said web and bearing against said web to form a bight therein;

(b) an arm rotatably journaling one end of said generally cylindricalmember in the nature of a cantilever;

(c) a block pivotally supporting said arm for pivotation of said rollerabout an axis extending substantially parallel to the bisector of theangle formed by said bight;

(d) a fixed raceway slidably journaling said block for movement in adirection generally normal to the direction of travel of said web;

(e) means secured to said raceway `and acting on said arm duringmovement of said block to pivot said arm and roller about said pivotalaxis; and

(f) means for shifting said block in response to transverse movements ofsaid web relative to a desired path of travel to effect correction ofthe misalignment of said web.

13. Apparatus for maintaining the alignment of a moving web comprising:

(a) an elongated cantilevered guide means contacting the web along oneof its surfaces in a direction transverse to the path of travel of theweb;

(b) means rotatably journaling said cantilevered guide means andsupporting said guide means in the nature of a cantilever;

(c) a slidably mounted bearing block pivotally supporting saidcantilevered guide means supporting means for pivotation about an axisextending through and substantially normal to the axis of rotation orsaid cantilevered guide means;

(d) a camming device contacting said guide means supporting means andpivoting said guide means supporting means in said bearing block duringsliding movement of said block; and

(e) means for shifting said block in response to transverse movements ofsaid Web relative to a desired path of travel to effect correction ofthe misalignment of said web.

14. A web guiding system for Iguiding a traveling web comprising:

(a) a cantilevered roller extending transversely to the path of travelof said web with an arcuate portion of its periphery in frictionalengagement with said web;

(b) a raceway assembly;

(c) a bearing block slidably mounted on said raceway assembly;

(d) a bracket rotatably journaling said roller at its supported end;

(e) a base plate secured to said bracket and extending parallel to saidroller;

(f) a shaft extending from one side of said base plate into said bearingblock;

(g) means for pivoting said cantilevered roller relative to said racewayand the longitudinal axis of said web as said roller supporting meansreciprocates on said raceway; and

(h) means for correlating the transverse movements of said web relativeto a predetermined path of travel with the movements of saidcantilevered roller and said roller journaling bracket to maintain thetransverse alignment of said web.

15. A web guiding system for guiding a traveling web comprising:

(a) a cantilevered roller extending transversely to the path of travelof said web with an arcuate portion of its periphery in frictionalengagement with said web;

(b) a :raceway assembly;

(c) means slidably and reciprocably mounted on said raceway assembly forpivotally supporting said cantilevered roller;

(d) an arcuate cam surface on said reciprocably mounted cantileveredroller supporting means;

(e) a cam follower secured on said raceway assembly and cooperating withsaid arcuate cam surface during :reciproca-ting movement of saidcantilevered roller to pivo-t said roller; and

(f) means for correlating the transverse movements of said web relativeto a predetermined path of travel with the movements of saidcantilevered roller and said roller supporting means to maintain lthetransverse alignment of said we-b.

16. A web guiding system as claimed in claim 15 wherein said arcuate camsurface is formed as an arcuate slot in said cantilevered rollersupporting means; and wherein said cam follower comprises a rollerrotatably mounted on said raceway assembly and projecting into saidarcuate slot.

References Cited by the Examiner UNITED STATES PATENTS 7/1963 Shelton226-22 9/1963 Fife 226--22

1. A WEB GUIDING SYSTEM FOR GUIDING A TRAVELING WEB COMPRISING: (A) ACANTILEVERED ROLLER EXTENDING TRAVERSELY TO THE PATH OF TRAVEL OF SAIDWEB WITH AN ARCUATE PORTION OF ITS PERIPHERY IN FRICTIONAL ENGAGEMENTWITH SAID WEB; (B) A RACEWAY ASSEMBLY; (C) MEANS SLIDABLY ANDRECIPROCABLY MOUNTED ON SAID RACEWAY ASSEMBLY FOR PIVOTALLY SUPPORTINGSAID CANTILEVERED ROLLER; (D) MEANS ON SAID RACEWAY ASSEMBLY ANDCOOPERATING WITH SAID ROLLER SUPPORTING MEANS FOR PIVOTING SAIDCANTILEVERED ROLLER RELATIVE TO SAID RACEWAY ASSEMBLY AND THELONGITUDINAL AXIS OF SAID WEB AS SAID ROLLER SUPPORTING MEANSRECIPROCATES ON SAID RACEWAY ASSEMBLY; AND (E) MEANS FOR CORRELATING THETRANSVERSE MOVEMENTS OF SAID WEB RELATIVE TO A PREDETERMINED PATH OFTRAVEL WITH MOVEMENTS OF SAID CANTILEVERED ROLLER AND ROLLER SUPPORTINGMEANS TO MAINTAIN THE TRANSVERSE ALIGNMENT OF SAID WEB.